In general, a method of placing reinforcing strips for constructing a precast concrete facing panel using reinforcing strips made of construction fabrics (called a “WEBSOL” technique) is performed by steps of placing and curing base concrete at level on the ground where a facing panel is to be installed to a depth of 20 cm and a width of 40 to 50 cm, installing a prop before mounting reinforcing strips made of fabrics for the purpose of preventing deformation which may arise when a concrete facing panel (retaining wall) is mounted on the base concrete and backfill soil is hardened, installing a clamp between panels for the purpose of preventing deformation which may arise when a concrete facing panel (retaining wall) is mounted on the base concrete and backfill soil is hardened and then inserting a vertical batten filler made of construction fabrics for use in highly water-permeable filter for drainage from the backfill soil, installing a key-wood on a joint of the front face of the concrete facing panel to a predetermined height until the processes of forming retaining soil to a predetermined height and hardening the same are completed, for the purposes of maintaining linearity of the installed concrete facing panel and preventing deformation thereof, connecting the reinforcing fabrics to a fixed reinforcing iron bar provided at the rear portion fixed by a fixing hook buried into the internal side of the facing panel and an anchor in a zigzag pattern and pulling up the same manually, laying a backfill material on the reinforcing strip and applying vibration and pressure to the resultant structure to have a predetermined thickness using a heavy equipment for hardening the resultant structure, and repeating the hardening step until approximately 2 m upward from the facing panel is reached using a small-sized hardening equipment while piling up the facing panel.
The conventional method of constructing a precast concrete facing panel poses various problems and difficulties in terms of working efficiency. That is to say, at least 4 to 5 worker must be involved in interconnecting the reinforcing strips between the interior surface of the facing panel and the fixed reinforcing iron bar in a zigzag pattern. In detail, manually pulling-up the reinforcing strips requires 2 or 3 workers, pressing the reinforcing strips at a bent portion at the fixing hook of the facing panel side requires at least one worker, and inducing the reinforcing strips reversed at the fixing iron bar and pulling up the same requires at least one worker. However, in the case where the length of each of the reinforcing strips to be constructed is increased as per specification, at least 7 to 8 workers are required. In particular, the worker in charge of the pulling-up work experiences physical fatigue and lowered working efficiency because the reinforcing strip is too wide and high for the worker to be pulled up by hand, e.g. as wide as approximately 10 cm. Also, it is quite difficult to pull up the reinforcing strips with a constant tension, resulting in a deformed facing panel, that is, a potbellied or twisted facing panel, after completing the placement, due to the loosened reinforcing strips remaining on the reinforcing soil member.
Several attempts to prevent the reinforcing strips from being loosened have been made, including a method of laying a reinforcing soil member using a heavy equipment in a state in which the reinforcing strips are forcibly pulled up such that a worker locks a lever in front of a fixing iron bar to be pushed away rearward, and a method of partially digging reinforcing strips and laying a reinforcing soil member thereon so that the reinforcing strips are pulled up while the dig portion of the reinforcing strips is buried. However, these methods are not so effective in preventing the reinforcing strips from being loosened and for applying an appropriate tension to the reinforcing strips. That is, since a most severely loosened portion of the reinforcing strips connected between the concrete facing panel and the fixing iron bar correspond to bent portions of the fixing hook at the interior surface of the concrete and the fixing iron bar at the rear end of the reinforcing soil member, the loosening of these portions cannot be effectively eased by the above-reference methods.